Electronic devices comprise a growing number of electronic components, some of which generate large amount of excess heat and some of which are more sensitive to heat, causing the electronics to malfunction, sometimes temporary and sometimes permanently.
This has become a growing concern in the electronics industry, especially with the ongoing development of smaller and smaller electronic devices concurrent with the increasing number of electronic elements on a given area. Consequently, it has become increasingly difficult to eliminate unwanted influence between these components, such as for instance due to heat emission. In the process of finding a remedy to this, it has therefore been attempted to designigning these devices so that heat emitting components and other components are separated from one another.
For instance, one specific field in which this has become a tangible problem is within large-volume application of high-brightness Light Emitting Diodes (LED) that are well established for signalling and signage. These diodes are expected to replace conventional lamps in lighting applications within a few years.
Electronic devices are today commonly referred to as being chip-based. A known principle to achieve a compact multi-chip module is to use naked LED chips mounted on a common substrate, such as one fabricated in silicon. In this substrate, more and more electronic components are integrated, for instance active components such as diodes and transistors as wells as passive components such as resistors, capacitors and inductors. These components set the color and flux setting of the light output of the multi-chip module.
Due to the light emitting characteristics of the LEDs, a large amount, around 80%, of the input power is dissipated in heat. As a consequence, this heat elevates the junction temperature of the LED and decrease the lifetime and the efficiency of it. Furthermore, more and more frequently it occurs that the LED junction temperature is rising at levels higher than 150° C., sometimes even as high as 185° C. In this range of temperature, the functionality of the electronic devices is strongly affected and impact the good light control of a Multi-chip module.
In order to maintain a good light control of such lighting modules, it is essential that the temperature of at the LED junctions is maintained below a certain threshold value. Hence, it is desirable for finding ways to increase the heat dissipation and protect the electronic devices from the excess heat.
US Patent Application 2005/0074046 discloses a heat generating diode chip, such as a laser diode, being separated from electrical circuitry by a heat sink and a thermal insulation layer so that heat generated by the light emitting element is not transmitted to the driver chip.
However, a number of drawabacks are associated with the devices of the prior art. It is therefore requested an alternative, convenient solution to shielding off heat sensitive components integrated in a substrate.